A conventional clutch such as a serrated coupling or a jaw coupling generally includes a plurality of interlocking teeth or jaws formed on their inner contact surfaces which can be engaged or disengaged for connecting or disconnecting two shaft portions. However, when it is intended to couple two coupling members of the clutch under running especially at high speed revolution, the teeth or jaws may be worn or damaged when closely contacted with each other. Meanwhile, such an engaging operation of the clutch coupling is always manually done by a liner sliding movement of the coupling members, possibly delaying a coupling operation and causing inconvenience for an operator.
The present inventor has found the drawbacks of the conventional clutch, and invented the present clutch which can be operated continuously during machine running.